Island



(No Model.)

J. MUIR. EXPANSION EULLEY.

No.. 541,870. Patented July 2, 1895.

Witnesses.

Nrra I STATES ATE-NT OFFI JAMES MUIR, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE PHENIX IRON FOUNDRY, OF SAME PLACE.

EXPANSlON-PULLEY.

SPECIFICATION forming part of Letters Patent No. 541,870, dated July 2, 1895.

Application filed. February 12, 1894. Serial No. 499,916. (No model.)

To all whom it may concern: not readily-accessible, in case of inspection or Be it known that 1, JAMES MUIR, a subject repair. Moreover, it sometimes happens that of the Queen of Great Britain, residing at the pulley is expanded to such an extent that Providence, in the county of Providence and the teeth or threads upon the arms of the seg- 5 State of Rhode Island, have invented certain ments do not have sufficient holding capacnew and useful-Improvements in Expansionity, the result being that the segments are Pulleys; and I do hereby declare the following liable to be thrown out by centrifugal force to be a full, clear, and exact description of the when the pulley is running at comparatively invention, such as will enable others skilled high speeds. 10 in the art to which it appertains to make and By means of my improvement the space reuse the same, reference being had to the acquired upon the shaft for the pulley need not companying drawings, and to letters of referexceed that required for an. ordinary pulley ence marked thereon, which form a part of having medium width; it is more cheaply this specification. made and at the same time more accurately 15 My present invention relates to improveoperated and adjusted, and each arm may be ments in expansion pulleys, that is, pulleys readily exposed by simply removing the corin which the rim portions are composed of a responding cover or cap, and finally by the series of sectors adapted to be actuated in a employment of suitable stop-pins the pulley radial direction simultaneously; and it concannot be expanded beyond a fixed or safe 2o sists essentially in the combination, with the limit.

hub or spider portion and screw-threaded In the accompanying sheet of drawings,Figarm-carrying sectors movably mounted thereure 1 is a front view of an expansion pulley in, of a spirally grooved face-plate loosely provided with my improvement, a portion of mounted on said hub and in engagement with the operating disk or face-plate being omitted. 2 5 the sector-arms, means for securing the face- Fig. 2 is a horizontal sectional view, taken on platein position upon the hub, a collarsecured line as or of Fig. 1. Fig. 3 is a rear elevation of to the end of the hub and in frictional conthe disk itself. Fig. 4 is an elevation of the tact with the outer end of the face-plate, stoppulley, viewed from the rear. Fig. 5 is a crosspinspassing through the spider-arms andinto sectional view of one of the arms, taken on o slotted openings formed in the back of the line 1) o, Fig. 1, and Fig. 6 is a front view of sector-arms, and removably secured caps for one of the arm-caps or covers, detached. covering and protecting the portions of the My improved pulley complete is indicated spider and arms extending beyond the rim of by A. As drawn, it is provided with a hub the face-plate, all as will be more fully hereportion or having a spider or spoke portion 8 3 5 inafter set forth and claimed. a integral therewith and extending radially In expansion pulleys as hitherto devised, in therefrom, in which are mounted the arms 4" which the arms and rim-sectors are adapted of the six rim-sectors r. The hub a is bored to be moved in a radial direction by means of a out to fit the shaft, as common to any pulley; spirally grooved or screw-threaded disk, it has that is to say,it may be keyed to the shaft or 40 been usual toemploy gearing or other equivaarranged to revolve on it as desired. The lent devices for rotating the disk, although in spokes of the spider portion are machined to some cases the disk, 850., have been so conformagrooved seatfortheseveral armsr; the structed that the rim-sectors may be actuated outer ends of the spokes being provided with without the intervention of gearing. An obside ears m which are drilled to receive bolts 5 5 jection to such former devices is that the disk m. To the front end of the hub is removably or operating wheel is as a rule located quite a secured an annular collar 0 whose outer edge distance from the pulley-rim. When thus conportion extends beyond the barrel of the hub structed the pulley occupies a much greater for the purpose of maintaining the expansion space on the shaft than an ordinary pulley face-plate or disk d in position. The several 10 5'0 having the same width of rim or face. Anrim-sectors r are turned off true to receive a other objection is that each individual armis belt, each sector being provided with an arm r fitted to move radially in the seat formed in the corresponding spider-spoke a. The front side of each arm is furnished with a series of raised ribs; the latter being arranged to form parts of a spiral or screw-thread t, as clearly shown. The faces of the arms are practically flush with the faces of the spokes, while the ribs t extend beyond said faces.

The front portion of the hub a is turned off true to form a support for the disk cl. This disk, or expanding face-plate, just fills the distance between the adjacent faces of the collar 0 and the spokes and is bored out to fit the said turned portion of the hub. When mounted thereon it will be apparent that while the disk is prevented from endwise movement, yet it is adapted to be freely revolved in either direction upon the hub; a

, set-screw d being employed to secure the disk in position after adjustment. In the face of the disk is cut a spiral groove 25 the same forming the counterpart of the ribs 25 of the sector-arms. The disk is further provided with a circular rim (1, and is connected therewith through the medium of short arms d as clearly shown. It will be seen that the disk and its rim occupy a comparatively small space longitudinally of the shaft, although ample room is provided for manipulating them. Between the outer edge or periphery of the disk, which is turned off true, and the root of the sector-arms are located cap-plates 6. These caps serve to cover and protect the adjacent front portion of the arms and are secured in place by bolts m which pass through the'caps and ears 1% located at the sides of the arms. The lower or inner ends e of the caps are made concave to fit the curvature of the disk the opposite or outer ends extending to-and terminating with the corresponding ends of the spokes a.

At or near the outer end of each of the spokes a is mounted a bolt or stop-pinf, its inner end extending through the spoke and into an elongated radial opening f formed in the rear face of the corresponding segment-arm r, as clearly shown in Figs. 2 and 4. These slotted openings, f, practically control and limit the radial movement of the segments, the relation of the inner end of the openings with respect to the stop-pins being such that the segments cannot be expanded too far, since the pins will arrest the segments movement before all the teeth or threads i become disengaged from the spiral groove 75 of the operating disk 01. The arrangement further serves as a safety device in that .the pinf will prevent the segment from flying outwardly in case the holding thread 15 becomes accidentally broken. Another advantage of the pin is that it can be so set or adjusted as to take up the wear and prevent rattling of the segment-arm.

I am well aware that expansion pulleys have been produced prior to my invention, and that the several segments have been operated simultaneously through the medium of screw-threads. Therefore I do not claim such broadly, but

What I do claim is Y As an improved article of manufacture, the expansion pulley A, hereinbefore described, the same consisting of the hub member at having a series of radiating spokes a provided each with a correspondingly arranged seat, a series of independent rim-sectors 0" having arms 1" slidably mounted in said spoke seats and having the front faces of said arms provided with sections of spiral threads If, a face-plate d mounted on and capable of being adjustably secured to said hub and having a spiral thread formed in its face in engagement with those of the sector-arms, capse secured to the front outer end portions of the said spokes a andexterior to the face plate, and stop-pins or bolts f adj ustably secured to the spokes, each pin having an end extending therethrough and in engagement with a slotted opening f formed in the back of the corresponding sector-arm, substantially as shown and described.

In testimony whereof I have affixed my signature in presence of two witnesses.

JAMES M UIR. Witnesses:

Gno. H. REMINGTON, IDA M. WARREN. 

